High density housing

An apartment (American English), flat (British English) or unit (Australian English) is a self-contained housing unit (a type of residential real estate) that occupies only part of a building, generally on a single storey. There are many names for these overall buildings, see below. The housing tenure of apartments also varies considerably, from large-scale public housing, to owner occupancy within what is legally a condominium (strata title or commonhold), to tenants renting from a private landlord (see leasehold estate).

Both words refer to a self-contained residential unit, i.e. one with its own front door, kitchen, toilet (room) and bathroom. In some parts of the world, the word apartment refers to a purpose-built unit in a building, whereas the word flat means a converted unit in an older building, usually a big house. In other places the terms are interchangeable.

The term apartment is favored in North America (although in some cities flat is used for a unit which is part of a house containing two or three units, typically one to a floor). In the UK, the term apartment is more usual in professional real estate and architectural circles where otherwise the term flat is used commonly, but not exclusively, for an apartment on a single level (hence a 'flat' apartment).

An apartment is in a building or converted house in which no space or single unit occupies an entire floor on its own. An apartment is like a subdivision of something bigger.

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